The present invention relates to digital data processors, and, in particular, to methods and apparatus for cooling components within a digital data processor or ancillary device. The invention has particular application in compact, xe2x80x9clow profilexe2x80x9d devices where space is at a premium, airflow paths are restricted and overheating is of concern.
Heating is a constant and significant problem in digital data processors. The failure rates of many electronic components increase as operating temperatures rise. This is particularly true of central processing units which, themselves, often generate significant heat. The problem is compounded by the use of more densely packed circuit boards, by faster processor chips, and by the large power supplies needed to support the foregoing.
Most often, processors and associated components are cooled by airflow. Fans are typically used to push or pull air from one side of a chassis, across the components, and out the other side of the chassis. Thus, for example, a typical digital data processor includes chassis intake and/or exhaust fans, often with a fan on the central processing unit itself. While the steps of simply providing intake and exhaust fans on a chassis or housing wall, and of providing one or more device fans on critical components, have proven adequate to date, there remains a need to provide for the cooling of even more powerful, and/or more compact systems.
One object of the present invention is to provide an improved digital data processor apparatus and methods.
A more particular object is to provide such apparatus and methods for cooling components of digital data processors.
A more particular object is to provide such apparatus and methods as are particularly adapted to cooling an integrated circuit chip element, such as a central processing unit, utilized in digital data processing apparatus.
A still further object of the invention is to provide such apparatus and methods as are adapted for use with web servers and other data processing apparatus that are housed in restricted space, are compact of design and/or are intolerant of overheating.
A still further object is to provide such apparatus and methods as can be implemented at low cost.
A still further object of the invention is to provide such apparatus and methods as can be adapted or retrofitted to pre-existing equipment, as well as designed for use in new equipment.
One or more of the foregoing objects are achieved in accordance with the present invention by a ventilating or cooling device that includes a fan adapted to mount within a housing, such as the housing or chassis of a web server or storage array, and to selectively cool one or more components disposed on a circuit board or chip carrier within the housing. A flow of air may be provided though the housing for general circulation and cooling, and the fan is positioned obliquely to redirect air toward or away from the selected component while maintaining, establishing or reinforcing a flow of air toward other components or along a path to the housing exhaust. The angle of the fan thus integrates the cooling air for the component in the region around the selected component into an airflow pattern through the chassis. By introducing a locally angled flow path, the fan avoids creation of turbulence or a cross-directed wind that would block overall chassis air flow, create back pressure or otherwise diminish the achievable cooling of the chassis components and the device as a whole.
In one embodiment the fan may be a muffin fan formed with an integral housing defining a plane of rotation for the fan blade, and mounted so that the fan blade lies at an oblique angle with respect to plane of the underlying circuit board or a component mounted on the board. In other embodiments the fan may mount with an inclination that introduces a downward component of airflow velocity, and/or a side-to-side tilt that directs the stream somewhat to the left or right to define a desired flow pattern within the chassis and around the components mounted in a housing. A particular embodiment mounts at a shallow angle to fit within a broad covered housing or chassis unit of low height, such as a web server or storage array device that mounts in a rack and that is densely populated with many circuit boards and/or other electronic components. The angle of the fan is tilted out of the horizontal plane to place its inlet facing the upstream or cooling inlet side of the housing, such that the air propelled by the fan has components of motion in both downward (toward the component) and downstream (toward an outlet) directions. For a chassis having an air inlet at the front, the fan maintains the coolant flow generally toward the rear of the housing, where vents and/or an outlet fan operate to maintain a suitable flow gradient over all devices in the housing. The angle of the fan may be defined by an integral mounting structure such as angled side plates formed in the exterior portion of the fan framework, or the oblique mounting angle may be achieved by using separate posts, angled mounting plates or other chassis attachments to define the position and orientation of the fan as a whole.
In yet further embodiments, the fan may possess an outer frame configured to provide a housing or shroud around the component which is to be cooled, and may have louvers or vents along one side of the shroud to define a desired downstream or side-diverted airflow directionality that integrates into the general circulation through the chassis.
The fan may be mounted on a heat sink having a conventional structure, such as a thermally conductive plate having a central flat region, and carrying a plurality of heat-dissipating fins or posts.
In accordance with further aspects of the invention, there is provided a component such as a web server in a chassis or housing for use in a digital data processing system. The component has one or more fans that define cooling airflow through the chassis, and includes a circuit element, such as a central processing unit, and an oblique fan as described above that cools the circuit element while integrating its stream into the chassis airflow. The fan may mount on a heat sink and introduce its downstream outflow into an airstream that has been somewhat straightened or blocked by fins of the heat sink, thus reinforcing or enhancing the overall chassis cooling.
The aforementioned objects are met by the present invention which provides, in one aspect, a cooling element for components within a digital data processor chassis. The cooling element, a fan or other device for actively inducing airflow, is disposed on or near the component to be cooled. It is disposed at an angle to facilitate a flow of air past the component and into an air stream established in the chassis.
Further aspects of the invention provide a cooling element (e.g., angled fan) as described above that includes a mounting plate to facilitate mounting the fan on the component being cooled.
Still further aspects of the invention include a mounting plate to mount the cooling element on the component.
In another aspect of the invention, a component is disposed within the rear portion of a chassis having a front, middle, and rear portion. The fan is angled toward the rear portion so as to direct airflow towards the component.
These and other aspects of the invention are evident in the drawings and in the descriptions that follow.